The Breusch-Pagan test tests for conditional heteroskedasticity.
The test statistics is computed by regressing squared residuals from the original regression against the original regressors (plus intercept).
The test is a chi-squared test: the test statistic distribution is nχ2 with k degrees of freedom.
If the Breush-Pagan test shows that there is conditional heteroscedasticity,
it can be corrected by using the Hansen method, using robust standard errors, or re-thinking the regression equation.